OP may have to remove the valve cover to replace a vintage PCV grommet. Can try first without removing the cover. But if a chunk does go back in, it's safest to remove the cover to finish the job. There's a plate inside the cover that may or may not prevent a chunk from finding its way to the...
If you go to the trouble of cleaning the intake, recommend a catch can to keep much of the future crud out. I've run one for a couple years. Nothing exotic, just the Husky brand plastic, compressed-air can. It indicates to me that I'm due for guide seals at least. :facepalm: